public class myprogram {
    public static void main(String[] args) {
        String a = "hello";
        String b = "world";
        String c = a + b;
        System.out.println(c);

        String str = "result = ";
        int a1 = 10;
        int b1 = 20;
        String result = str + a1 + b1;
        System.out.println(result);
        // 执行结果result = 1020

        int a2 = 10;
        int b2 = 20;
        System.out.println("a2 = " + a2 + ",b2 = " + b2);
    }
}
